Server and networking systems are incorporating co-packaging of application-specific integrated circuit (ASIC) and optical communication components. With co-packaging, ASIC and optical components are assembled in very close proximity with spacings as close as one mm, or less. In some cases, active optical devices, such as lasers and photodetectors, are being assembled directly onto ASIC chips.
Compact electrical circuit board substrates, called interposers, can be useful in assembling co-packaged optics. The interposer serves as an intermediate assembly structure onto which multiple active optical devices can be solder-attached and tested, with a high yield of good components.